TENS or Transcutaneous Electrical Neural Stimulation is more appropriately called Ultra-Low Frequency (ULF) electrical muscle stimulation in Neuromuscular Dentistry.
Neuromuscular Dentistry (neuro=nerves and muscular=muscles) is a science of dentistry that evaluates the complex relationship between teeth, temporomandibular joints (TMJ), muscles and nerves to find out the best resting position of the jaw (occlusion). This occlusion may or may not be ideal. In cases of misaligned occlusion, the stressed muscles of TMJ need to be relaxed so as to find their true resting state and establish the occlusion at that position. This is done by TENS as it is very difficult to voluntarily relax these muscles. In addition to this, TENS is secondarily used to achieve drug-free pain relief in TMD.